Diarrhea

What Is Diarrhoea? Causes, Symptoms and When Testing Is Needed

Diarrhoea is defined as passing loose or watery stools three or more times a day, or a marked increase compared with a person's usual bowel habits. Infections are among the common causes; viruses, bacteria and parasites can cause diarrhoea. Certain medicines and other health conditions can also cause diarrhoea.

How does diarrhoea spread?

Infectious diarrhoea can spread mainly through consuming water or food contaminated with germs, or from person to person when hand hygiene is inadequate. Safe drinking water, handwashing, proper food preparation and storage, and hygiene after using the toilet reduce the risk of transmission.

What are the symptoms of diarrhoea?

Frequent, watery stools may be accompanied by abdominal cramps, nausea, vomiting or fever. One of the most important risks is dehydration caused by the loss of fluids and electrolytes through stools and vomiting. A dry mouth, reduced urination, dizziness and marked weakness may indicate dehydration.

When should I see a doctor for diarrhoea?

Seek medical assessment without delay in the following situations:

1. If there is blood in the stool
2. If there is a high fever or severe abdominal pain
3. If you cannot drink fluids or vomit after drinking them
4. If urination has decreased significantly, your mouth is very dry or you feel dizzy when standing up
5. If diarrhoea lasts longer than a few days or symptoms worsen rapidly
6. If the patient is a young child, an older person, someone who is immunocompromised or someone with a serious chronic illness

The CDC recommends seeing a doctor for bloody diarrhoea, diarrhoea lasting longer than three days, a high fever, inability to keep fluids down or signs of dehydration.

Which tests may be needed for diarrhoea?

Laboratory testing is often unnecessary for mild, short-lived diarrhoea that resolves on its own. A doctor may request stool testing in situations involving fever, bloody or mucus-containing stools, severe abdominal pain, signs of sepsis, prolonged diarrhoea, immunosuppression or a possible outbreak. Recent travel, antibiotic use or contact with people who have similar symptoms may also influence which tests are selected.

The testing method is selected according to the suspected pathogen. Stool culture can allow certain bacteria to be grown and identified; molecular tests such as PCR look for the genetic material of pathogens included in the panel. No single test detects every cause of diarrhoea; the appropriate sample and test should be selected based on clinical assessment. The IDSA identifies a stool sample as the preferred specimen for diagnosing infectious diarrhoea.

How is diarrhoea treated?

The main approach to diarrhoea is to replace lost fluids and electrolytes. Oral rehydration solution (ORS) may be used for mild or moderate dehydration. Taking small, frequent sips of fluid may help. It is important to continue breastfeeding and appropriate feeding in infants. If severe dehydration or shock develops, intravenous fluids may be needed in a healthcare facility.

Antibiotics do not treat every case of diarrhoea; they are ineffective against viral diarrhoea and may be unnecessary or harmful in certain bacterial infections. If you have bloody diarrhoea or a fever, do not use antidiarrhoeal medicines without a doctor's advice. Always consult a healthcare professional before giving medicines to children.

What can be done to prevent diarrhoea?

1. Wash your hands with soap after using the toilet and before preparing food.
2. Use safe drinking water.
3. Keep raw and cooked foods separate; cook and store food at appropriate temperatures.
4. Wash fruit and vegetables with clean water.
5. Discuss the rotavirus vaccine recommended in the vaccination schedule with your paediatrician.